add token/token_transfer existance methods

apps/block_scout_web/lib/block_scout_web/controllers/tokens/instance_controller.ex

@@ -5,9 +5,8 @@ defmodule BlockScoutWeb.Tokens.InstanceController do
 
   def show(conn, %{"token_id" => token_id, "id" => token_address_hash}) do
     with {:ok, hash} <- Chain.string_to_address_hash(token_address_hash),
-         {:ok, _token_address} <- Chain.token_from_address_hash(hash, []),
+         :ok <- Chain.check_token_exists(hash),
-         {:ok, _token_transfer} <-
+         :ok <- Chain.check_erc721_token_instance_exists(token_id, hash) do
-           Chain.erc721_token_instance_from_token_id_and_token_address(token_id, hash) do
       redirect(conn, to: token_instance_transfer_path(conn, :index, token_id, token_address_hash))
     else
       _ ->

apps/explorer/lib/explorer/chain.ex

@@ -3616,6 +3616,115 @@ defmodule Explorer.Chain do
     Repo.exists?(query)
   end
 
+  @doc """
+  Checks if a `t:Explorer.Chain.Token.t/0` with the given `hash` exists.
+
+  Returns `:ok` if found
+
+      iex> address = insert(:address)
+      iex> insert(:token, contract_address: address)
+      iex> Explorer.Chain.check_token_exists(address.hash)
+      :ok
+
+  Returns `:not_found` if not found
+
+      iex> {:ok, hash} = Explorer.Chain.string_to_address_hash("0x5aaeb6053f3e94c9b9a09f33669435e7ef1beaed")
+      iex> Explorer.Chain.check_token_exists(hash)
+      :not_found
+  """
+  @spec check_token_exists(Hash.Address.t()) :: :ok | :not_found
+  def check_token_exists(hash) do
+    hash
+    |> token_exists?()
+    |> boolean_to_check_result()
+  end
+
+  @doc """
+  Checks if a `t:Explorer.Chain.Token.t/0` with the given `hash` exists.
+
+  Returns `true` if found
+
+      iex> address = insert(:address)
+      iex> insert(:token, contract_address: address)
+      iex> Explorer.Chain.token_exists?(address.hash)
+      true
+
+  Returns `false` if not found
+
+      iex> {:ok, hash} = Explorer.Chain.string_to_address_hash("0x5aaeb6053f3e94c9b9a09f33669435e7ef1beaed")
+      iex> Explorer.Chain.token_exists?(hash)
+      false
+  """
+  @spec token_exists?(Hash.Address.t()) :: boolean()
+  def token_exists?(hash) do
+    query =
+      from(
+        token in Token,
+        where: token.contract_address_hash == ^hash
+      )
+
+    Repo.exists?(query)
+  end
+
+  @doc """
+  Checks if a `t:Explorer.Chain.TokenTransfer.t/0` with the given `hash` and `token_id` exists.
+
+  Returns `:ok` if found
+
+      iex> contract_address = insert(:address)
+      iex> token_id = 10
+      iex> insert(:token_transfer,
+      ...>  from_address: contract_address,
+      ...>  token_contract_address: contract_address,
+      ...>  token_id: token_id
+      ...> )
+      iex> Explorer.Chain.check_erc721_token_instance_exists(token_id, contract_address.hash)
+      :ok
+
+  Returns `:not_found` if not found
+
+      iex> {:ok, hash} = Explorer.Chain.string_to_address_hash("0x5aaeb6053f3e94c9b9a09f33669435e7ef1beaed")
+      iex> Explorer.Chain.check_erc721_token_instance_exists(10, hash)
+      :not_found
+  """
+  @spec check_erc721_token_instance_exists(binary() | non_neg_integer(), Hash.Address.t()) :: :ok | :not_found
+  def check_erc721_token_instance_exists(token_id, hash) do
+    token_id
+    |> erc721_token_instance_exist?(hash)
+    |> boolean_to_check_result()
+  end
+
+  @doc """
+  Checks if a `t:Explorer.Chain.TokenTransfer.t/0` with the given `hash` and `token_id` exists.
+
+  Returns `true` if found
+
+      iex> contract_address = insert(:address)
+      iex> token_id = 10
+      iex> insert(:token_transfer,
+      ...>  from_address: contract_address,
+      ...>  token_contract_address: contract_address,
+      ...>  token_id: token_id
+      ...> )
+      iex> Explorer.Chain.erc721_token_instance_exist?(token_id, contract_address.hash)
+      true
+
+  Returns `false` if not found
+
+      iex> {:ok, hash} = Explorer.Chain.string_to_address_hash("0x5aaeb6053f3e94c9b9a09f33669435e7ef1beaed")
+      iex> Explorer.Chain.erc721_token_instance_exist?(10, hash)
+      false
+  """
+  @spec erc721_token_instance_exist?(binary() | non_neg_integer(), Hash.Address.t()) :: boolean()
+  def erc721_token_instance_exist?(token_id, hash) do
+    query =
+      from(tt in TokenTransfer,
+        where: tt.token_contract_address_hash == ^hash and tt.token_id == ^token_id
+      )
+
+    Repo.exists?(query)
+  end
+
   defp boolean_to_check_result(true), do: :ok
 
   defp boolean_to_check_result(false), do: :not_found